In many industries, it is commonplace to provide thermal insulation for pipe and equipment to prevent heat loss or gain. There are a variety of insulation products that are conventionally used in the industry depending upon a number of parameters including the particular application for the product. Mineral wool is among the most frequently employed materials in thermal protection, noise control and fire-proofing applications. This is due to the fact that, on the one hand, mineral wool has excellent insulating characteristics and, on the other, is non-combustible (its melting point is above 1000° C.), water repellent, resistant to ageing and can be easily processed. The base material used for mineral wool is rock, such as for example basalt and dolomite as well as quartz sand and other mineral aggregates.
Mineral wool products generally comprise mineral fibers bonded together by a cured thermoset polymeric material. One or more streams of molten glass, slag or stone (at temperatures ranging between 1300° C. and 1600° C.) are drawn into fibers and blown into a forming chamber where they are deposited as a web on to a travelling conveyer. The fibers, while airborne in the forming chamber and while still hot are sprayed with a binder. The coated fibrous web is then transported from the chamber to a curing oven where heated air is blown through the mat to cure the binder and rigidly bond the mineral wool fibers together. The final products are commonly insulating boards used for thermal insulation, sound- and fire-proofing purposes.
While mineral wool possesses a number of advantageous properties, including its fire-proofing properties, it has an inferior thermal properties compared to competing products, such as fiberglass insulation. One common method for describing the thermal properties of insulation is by referencing its “R-value”. The R-value is a measure of thermal resistance used in the building and construction industry. Under uniform conditions it is the ratio of the temperature difference across an insulator and the heat flux. The R-value is thus a measure of insulation's heat loss retardation under specified test conditions. The primary mode of heat transfer impeded by insulation is conduction but unavoidably it also impedes heat loss by all three heat transfer modes: conduction, convection, and radiation. The primary means of heat loss across an uninsulated air-filled space is natural convection, which occurs because of changes in air density with temperature. Insulation greatly retards natural convection making the primary mode of heat transfer conduction. Recently, the Department of Energy has developed new insulation guidelines. These are minimum standards and set forth a minimum R-value for a given particular location.
It is therefore desirable to produce an insulation product thus offers the fire-proofing properties of mineral wool but also has improved thermal properties.